|
Eng ID | Term | Definition |
---|---|---|---|
|
3521 | obliquity of the ecliptic | The acute angle between the plane of the ECLIPTIC and the plane of the CELESTIAL EQUATOR, about 23° 27'. |
|
3522 | obscured | (adj.). Said of the arc of a LIGHT SECTOR designated by its limiting BEARINGS in which the LIGHT is not visible from seaward. |
|
3523 | observation | The act or practice of noting and recording facts and events as for some scientific study. The measure of a quantity whose value is desired... more |
|
3524 | observation(s): astronomical | OBSERVATIONS of CELESTIAL BODIES, with appropriate instruments. In NAVIGATION, the measurement of ALTITUDE and AZIMUTH of CELESTIAL BODIES. |
|
3525 | observation(s): magnetic | Measurement of any of the MAGNETIC ELEMENTS. |
|
3526 | observation(s): meteorological | Evaluation or measurement of one or more meteorological elements. |
|
3527 | observation(s): tidal | A series of measurements taken in order to provide the information required for the REDUCTION OF SOUNDINGS, and the DATA for TIDAL PREDICTI... more |
|
3528 | observation equation | See EQUATION. |
|
3529 | observation spot (or pillar) | A position ashore determined from celestial observations. |
|
3530 | observation tower | A tower from which one's surroundings can be observed, but at which a watch is not habitually maintained, as at a LOOKOUT TOWER. Such tower... more |
|
3531 | observed altitude | See ALTITUDE. |
|
3532 | observed tide | Those data from tide observing equipment such as tide gauges, staffs, etc. "Actual tides" is an expression often used in referring to "obse... more |
|
3533 | obstruction | In MARINE NAVIGATION, anything that hinders or prevents movement, particularly anything that endangers or prevents passage of a vessel. The... more |
|
3534 | obstruction buoy | A BUOY marking an OBSTRUCTION. |
|
3535 | obstruction light | See LIGHT. |
|
3536 | occasional light | See LIGHT. |
|
3537 | occluded front | See OCCLUSION. |
|
3538 | occlusion | Process of progressive decrease of area of warm sector at the EARTH's surface, and its ultimate disappearance, by the junction of the cold A... more |
|
3539 | occultation | The concealment or extinguishment of the light of an AID TO NAVIGATION during the dark periods of its CYCLE. In ASTRONOMY, the concealment ... more |
|
3540 | occupy | (v.t.). In SURVEYING, to observe with a surveying instrument at a STATION; also to set a surveying instrument over a point for the purpose o... more |